Obstacle detection systems for garage door openers are well known. One type of detector utilizes an infrared (IR) beam transmitted across the door opening and is sometimes to referred to as a "beam break" unit. In this obstruction detector system, an IR emitter and IR detector are disposed on opposite sides of the door opening and the emitter sends a beam of IR pulses to the receiver. If the beam is broken by an obstruction, the garage door opener (GDO) is signalled to inhibit initiation of door closure or, if the door is closing, to stop and reverse the movement of the door.